Nobuhiro Tsukada Architects' Plantable Earth House is Built Around a Column of Soil

Nobuhiro Tsukada Architects were charged will fulfilling their client's dream of a home organized around a central courtyard - but even in rural Tokyo land comes at a premium and planning restrictions can be sensitive. Due to these challenges the finished project doesn't have a ‘real’ courtyard garden - instead the architects centered the home around a 4.3-meter-tall funnel-shaped column of soil that provides thermal mass and creates space for a raised rooftop garden above.

Completed in 2010 by Nobuhiro Tsukada Architects, the Earth House is located in Misato, Saitma – a semi-rural region of Tokyo. The project was a true collaboration between architecture and the environment, as well as a true collaboration between architect Nobuhiro Tsukada and engineer Hiroshi Ohno. It was identified early in the design process that the underlying form of the house would be a central courtyard, to avoid prying eyes. However the plot of land was too small to accommodate both a comfortable living area and a sufficient outdoors space.

The solution was elegant and simple; after toying with the possibility of a courtyard design as well as a roof garden design and knowing that the client wanted a ‘real’ garden, with soil, that could be planted, Nobuhiro Tsukada devised a raised area that would combine the benefits of both options.

Strategically placed skylights puncture the curved concrete, breaking up the form while delivering daylight in to the functional rooms below. As the raised courtyard garden is directly connected to the ground, the owners will not face the problems associated with channeling run-off water. The funnel form collects the rainwater, which irrigates the garden and heads back to the water table by virtue of gravity.